Crane Dynamic Lift-Off Control With Load-Swing Filtering
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Solution Overview
Problem
Conventional dynamic lift-off control devices require complex control processes, leading to prolonged times for lifting off suspended loads while suppressing load swing.
Innovation Solution
A dynamic lift-off control device that includes a load detection unit and a control unit to control the winch and boom operations, using a filter to dampen specific frequency components, allowing quick lift-off with reduced swing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dynamic lift-off control devices use a winch actuator and a derricking actuator in combination to keep the work radius constant, then load swing is suppressed, but it takes time to perform the dynamic lift-off due to complicated control
Solution Approach 1:
The patent extracts and eliminates the derricking actuator from the conventional two-actuator system (winch + derricking actuator). Instead of using both actuators in combination, the invention uses only the winch actuator to perform dynamic lift-off by winding the wire rope, thereby simplifying the control system and reducing the time required while still suppressing load swing through the filter-based control method
Solution Approach 2:
The patent applies parameter changes by introducing a filter that modifies the control signal's frequency characteristics. The filter removes frequency components corresponding to the load swing natural frequency from the control signal, thereby suppressing load swing without requiring complex multi-actuator coordination, enabling faster single-actuator-based dynamic lift-off
2Reliability
If conventional dynamic lift-off control devices use complicated control processes to suppress load swing, then load swing is suppressed, but the control process takes prolonged time
Solution Approach 1:
The patent replaces complex mechanical control (coordination of multiple actuators) with a signal processing approach. By substituting the mechanical complexity of dual-actuator coordination with an electronic filter that processes the control signal, the system achieves load swing suppression through frequency domain manipulation rather than complex mechanical control, thereby increasing productivity
Solution Approach 2:
The patent introduces a filter as an intermediary element between the control signal generation and the winch actuator. This filter acts as a mediator that modifies the control signal by removing problematic frequency components, thereby suppressing load swing without requiring complicated direct control of multiple actuators, enabling faster and simpler control
Data Source
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AI summary
A dynamic lift-off control device that is mounted on a crane including a boom and a winch for winding a wire rope and that controls dynamic lift-off of a suspended load, wherein: the dynamic lift-off control device comprises a load detection unit that detects a load acting on the boom, and a control unit that controls a winding action of the winch and a hoisting action of the boom; and the control unit controls the hoisting of the boom by using a control signal, which is generated on the basis of the change over time in the value detected by the load detection unit and to which a filter for attenuating a frequency component in a prescribed range, to suppress swaying of the suspended load is applied.